"People SAY this but they don't know what it means. MEDIOCRE ideas are a dime a dozen, GOOD IDEAS are hard to come by."
I have to disagree with this. Before there was Google, there was thousands of people working on "search" who understood the end game but not how to get there. Thousands of smart people. Same thing with Facebook. Same thing with gearboxes, mechanical engineers, designers, chemists, business ventures, computer games, medical research etc.
Good ideas are easy to have and hard to execute - and I don't necessarily mean complex to execute. There many obstacles of getting things done: timelines, finance, communication, competence, team.
P.S. - I'm trying to figure out if there is irony with regard to Dunning–Kruger in your post, my post or both